A plurality of electronic control units (ECUs) in a vehicle are configured to control various electric components. The ECUs need to be diagnosed for checking on the overall vehicle state.
The number of ECUs mounted on a vehicle has been gradually increasing as the number of functions for convenience and safety of the vehicle increases. The ECUs are connected to each other through communication networks of various speeds according to the necessary communication environment.
According to a conventional ECU diagnosing method for a vehicle, diagnostic equipment and ECUs are connected to each other through on-board diagnostics (OBD) terminals of the vehicle. A diagnosis process for one ECU uses a one-to-one communication method between the diagnostic equipment and the ECUs, and a sequential diagnosis algorithm for diagnosing the next ECU is performed after the first ECU diagnosis process is completed.
An example of the conventional ECU diagnosing method for a vehicle will be described with reference to FIG. 1 hereinafter.
As shown in FIG. 1, ECU diagnostic equipment diagnoses four ECUs, including P-ECU(1), C-ECU(1), M-ECU(1), and B-ECU(1) connected to different communication channels, respectively. That is, the diagnostic equipment diagnoses the ECUs through one-to-one connections between the diagnostic equipment and the ECUs, and sequential diagnosis processes.
In more detail, in order to diagnose the plurality of ECUs, the diagnostic equipment completes diagnosis of P-ECU(1) of channel 1 (CH-1) and diagnoses C-ECU(1) of channel 2 (CH-2), completes diagnosis of C-ECU(1) of channel 2 (CH-2) and diagnoses M-ECU(1) of channel 3 (CH-3), and so on. In this way, the diagnostic equipment performs a total of five diagnosis processes.
Then, since the ECUs are connected through communication networks (for example, Ethernet: 100 Mbps, FlexRay: 2.5 Mbps to 10 Mbps, CAN: 100 Kbps to 1 Mbps, LIN: 10 to 40 Kbps, K-Line: 10.4 Kbps) of various speeds, the diagnosis process speeds of the diagnostic equipment are also influenced by the speeds of the communication networks.
The ECUs of specific devices, such as a plurality of electric components in the vehicle, which are connected through different networks and the diagnostic equipment, should be one-to-one connected to each other and sequentially diagnose the ECUs in order to check states of the specific devices. Therefore, data transmission time is different from each other according to the speeds of the networks connected to the ECUs, and the state information of all the devices can be identified through the information collected by the diagnostic equipment after all the diagnosis processes are sequentially performed.
Hereafter, the conventional ECU diagnosing method will be described in detail.
A plurality of ECUs configured in a vehicle are connected to each other through a communication gateway having networks of different speeds. Diagnosis processes between diagnostic equipment and the ECUs are performed through the communication gateway, and diagnostic information of the vehicle flows through a sequential path of diagnostic equipment, a network, a gateway, a network, an ECU, a network, the gateway, a network, and the diagnostic equipment.
For example, when P-ECU(1) is diagnosed as shown in FIG. 1, diagnostic information of the vehicle flows through a sequential path of the diagnostic equipment, a network D-CAN, the gateway, a network P-CAN, P-ECU(1), the network P-CAN, the gateway, the network D-CAN, and the diagnostic equipment.
In order to obtain one ECU information element, the diagnostic information should be transferred via a network, a gateway, and a network each time. Thereby, the transfer time of the generated diagnostic information data is increased in proportion to the number of ECUs.
In order to diagnose one ECU, the diagnostic equipment performs several transmissions and receptions of signals with the corresponding ECU. If a data transmission time through a network is Tn, the number of transmissions/receptions of the signals for a diagnosis of the ECU is N, the number of ECUs to be diagnosed is M, and the number of CAN communication networks (that can be changed according to the number of CAN communication networks) is 4, the data transmission time Tt for diagnosing the ECUs is expressed as in Equation 1, and the data transmission time Tt is significantly increased as the number of ECUs to be diagnosed is increased.Tt=M*N*4*Tn  Equation 1:
In Equation 1, a difference in transfer time Tn through a network is generated according to the transfer time of the network. When the data transmission time through an Ethernet communication network is “1e”, which has the fastest communication speed, it may be assumed that the data transmission time through a FlexRay communication network is “10e”, which has the second fastest speed, and the data transmission time through a CAN communication network is “100e”, which has the slowest speed.
In general, the data transmission time is 100 Mbps for the Ethernet, 10 Mbps for FlexRay, and 1 Mbps for CAN with reference to the maximum bit rate, respectively.
Here, an example of obtaining data transmission time when ECUs are diagnosed according to the related art will be described below.
As shown in FIG. 1, in a state in which an ECU diagnostic equipment for a vehicle and a gateway are connected to each other through a D-CAN network, the gateway and ECU(1), ECU(2), ECU(3), and ECU(4) are connected to each other through CAN communications P-CAN, C-CAN, M-CAN, and B-CAN, respectively. When the gateway and the ECU(5) are connected to each other through a FlexRay communication network, a total diagnosis time Tt is obtained in Equation 2.Tt=4*(200e+100e+100e+200e)+(200e+10e+100e+200e)=2820e  Equation 2:
It is assumed in Equation 2 that the number N of transmissions and receptions of signals for diagnosis of ECUs and a latency time through a gateway are omitted.
For example, when a diagnosis process for ECU(1) is performed, diagnostic information of a vehicle flows through a sequential path of diagnostic equipment, a network D-CAN, the gateway, a network P-CAN, P-ECU(1), a network P-CAN, the gateway, the network D-CAN, and the diagnostic equipment.
Referring to FIGS. 1 and 2, a total data transmission/reception time of 600e includes a CAN communication data transmission time 100e for which a signal is transmitted from the diagnostic equipment to the gateway via the network D-CAN, and a CAN communication data transmission time 100e for which a signal is transmitted from the gateway to CH-1 (P-CAN) connected to ECU(1). A CAN communication data transmission time 100e for which a signal is transmitted from CH-1 to ECU(1), and a CAN communication data reception time 100e for which a signal is transmitted from ECU(1) to CH-1 are consumed. The total data transmission/reception time of 600e further includes a CAN communication data transmission time 100e for which a signal is transmitted from CH-1 to the gateway, and a CAN communication data reception time 100e for which a signal is transmitted from the gateway to diagnostic equipment.
Then, since ECU(2), ECU(3), ECU(4), and ECU(1) are connected to the diagnostic equipment and the CAN communication network, the total data transmission/reception time of 600e is consumed.
ECU(5) is connected to a FlexRay communication network through the gateway and channel 5 (CH-5). Therefore, a data transmission time from CH-5 to ECU(5) of 10e and a data reception time from ECU(5) to CH-5 of 10e are consumed, and thus, the total data transmission/reception time of 420e is consumed.
In this way, when ECU(1) to ECU(5) to be diagnosed are connected to each other through different communication channels, the total time for which all information is transferred to the diagnostic equipment is 2820e.
Hereinafter, another example of obtaining a data transmission time when ECUs are diagnosed according to the related art will be described.
When five ECUs, that are connected to one identical CAN communication channel, are diagnosed to check states of the ECUs, a time Tt for which the entire diagnosis is performed is obtained as follows.Tt=5*(200e+100e+100e+200e)=3000e  Equation 3:
In Equation 3, the number of transmissions and receptions for diagnosis of the ECUs is assumed to be 1, and a latency time through the gateway is omitted.
Since the time for which one ECU is diagnosed is 600e (200e+100e+100e+200e), the total time for which all information of the ECUs to be diagnosed are transferred to the diagnostic equipment is 3000e when the five ECUs are connected to each other in series through the CAN communication channel is 3000e.
According to the ECU diagnosing method of the related art, since the ECUs of specific devices connected to each other through different communication networks should be one-to-one connected to the diagnostic equipment to be sequentially diagnosed, data transmission time will be different from each other according to the speeds of the networks connected to the ECUs, and it will require long hours for transmission/reception of diagnosis data.